Surgical robotic system and method for automatic grasping force adjustment during suturing

Abstract

A surgical robotic system includes a robotic arm having an instrument with a pair of opposing jaws configured for grasping, and an instrument drive unit configured to couple to and to actuate the instrument. The system also includes a surgeon console having a handle controller configured to control the robotic arm and the instrument. The system further includes a controller configured to: receive an electrical property of the opposing jaws; receive an angle of the opposing jaws; determine whether the opposing jaws are grasping a metallic object; and adjust a gripping force of the opposing jaws based on the determination.

What is claimed is: 
     
         1 . A surgical robotic system comprising:
 a robotic arm including an instrument having a pair of opposing jaws configured for grasping and an instrument drive unit configured to couple to and to actuate the instrument;   a surgeon console including a handle controller configured to control the robotic arm and the instrument; and   a controller configured to:
 receive an electrical property of the opposing jaws; 
 receive a measurement of an angle of the opposing jaws; 
 determine whether the opposing jaws are grasping a metallic object based on the electrical property and the angle of the opposing jaws to form a determination; and 
 adjust a gripping force of the opposing jaws based on the determination. 
   
     
     
         2 . The surgical robotic system according to  claim 1 , further comprising an electrical sensor configured to measure the electrical property. 
     
     
         3 . The surgical robotic system according to  claim 1 , wherein the electrical property is impedance. 
     
     
         4 . The surgical robotic system according to  claim 3 , wherein the controller is further configured to compare the impedance to a threshold impedance corresponding to the metallic object to determine whether the opposing jaws are grasping the metallic object. 
     
     
         5 . The surgical robotic system according to  claim 1 , wherein the metallic object is a suturing needle. 
     
     
         6 . The surgical robotic system according to  claim 5 , wherein the controller is further configured to measure the angle of the opposing jaws based on at least one of motor position, torque, or current. 
     
     
         7 . The surgical robotic system according to  claim 6 , wherein the controller is further configured to compare the measured angle to a threshold angle configured to grasp the needle to determine whether the opposing jaws are grasping the metallic object. 
     
     
         8 . The surgical robotic system according to  claim 5 , wherein the controller is further configured to:
 determine whether the opposing jaws are grasping the suturing needle based on the electrical property and the angle of the opposing jaws; and   adjust the gripping force of the opposing jaws based on the determination.   
     
     
         9 . The surgical robotic system according to  claim 8 , wherein during adjusting the gripping force, the controller is further configured to increase the gripping force in response to determining that the suturing needle is being grasped. 
     
     
         10 . The surgical robotic system according to  claim 8 , wherein during adjusting the gripping force, the controller is further configured to decrease the gripping force in response to determining that the suturing needle is not being grasped. 
     
     
         11 . A surgical robotic system comprising:
 a robotic arm including:
 an instrument having a pair of opposing jaws configured for grasping; and 
 an instrument drive unit configured to couple to the instrument, the instrument drive unit including:
 at least one motor configured to actuate the opposing jaws between an open configuration and a closed configuration; and 
 a sensor configured to determine an angle between the opposing jaws; 
 
   a surgeon console including a handle controller configured to control the robotic arm and the instrument;   an electrical sensor in electrical communication with the pair of opposing jaws and configured to measure an electrical property thereof the opposing jaws; and   a controller configured to:
 determine whether the opposing jaws are grasping a suturing needle based on the measured electrical property and the measured angle of the opposing jaws; and 
 adjust a gripping force of the opposing jaws based on the determination. 
   
     
     
         12 . The surgical robotic system according to  claim 11 , wherein the electrical property is impedance. 
     
     
         13 . The surgical robotic system according to  claim 12 , wherein in determining whether the opposing jaws are grasping the suturing needle, the controller is further configured to compare the impedance to a threshold impedance corresponding to the suturing needle. 
     
     
         14 . The surgical robotic system according to  claim 11 , wherein the sensor is a motor encoder configured to measure rotational output of the at least one motor, and the instrument drive unit includes a drive controller configured to calculate the angle based on the rotational output. 
     
     
         15 . The surgical robotic system according to  claim 11 , wherein the controller is further configured to increase the gripping force in response to determining that the suturing needle is being grasped. 
     
     
         16 . The surgical robotic system according to  claim 11 , wherein the controller is further configured to decrease the gripping force in response to determining that the suturing needle is not being grasped. 
     
     
         17 . A method for controlling a motorized instrument, the method comprising:
 measuring an electrical property of opposing jaws of the motorized instrument actuated by an instrument drive unit including at least one motor;   measuring an angle of the opposing jaws;   determining, at a controller, whether the opposing jaws are grasping a suturing needle based on the measured electrical property and the measured angle of the opposing jaws; and   adjusting torque of the at least one motor actuating the opposing jaws based on the determination.   
     
     
         18 . The method according to  claim 17 , further comprising increasing a gripping force of the opposing jaws in response to determining that the suturing needle is being grasped. 
     
     
         19 . The method according to  claim 17 , further comprising decreasing a gripping force of the opposing jaws in response to determining that the suturing needle is not being grasped. 
     
     
         20 . The method according to  claim 17 , wherein the electrical property is impedance, and the method further comprises comparing the impedance to a threshold impedance corresponding to the suturing needle.